An optic disc drive, such as CD-ROM and DVD, is an important data storage device of a computer system. The operational speed of the optic disc drive has been significantly increased recently. The high operational speed makes vibration caused by operation of motor or unbalance weight of a disc more severe for such a vibration may result in undesired access error. Thus it is desired to have a balancing device for achieving balance of rotation of an optic disc and reducing the vibration caused thereby during the operation of the optic disc drive.